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ИСТИНА ПсковГУ |
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Intraspecific variability of a modern human mandible was determined using a principal component method following by a varimax rotation. Individual standardized data for the following series were included in analysis: Eskimo from Ekven, 4-7 cen. AD, - 61 jaws; Eskimo from Naukan, 19-20 cen. AD, - 23 jaws; Anglo-Saxon from Dunstable, 5-6 cen. AD, - 40 jaws (Dingwall, Yaung, 1933); Ancient Egyptian series, IX dynasty, - 37 jaws (Woo, 1930); series of Badari culture, Egypt, 5-3 cen. BC, - 32 jaws (Stossiger, 1927); Hokiens, southeast China, early 20 century, - 38 jaws (Harrower, 1928); Hylams, island Hainan, China, - 39 jaws (Harrower, 1928); Tamils, India and Ceylon, - 33 jaws (Harrower, 1928). During the analysis we determined three principle components (PC-1, 2, 3). The first PC describes the overall size of a bone and is not associated with angular dimensions. PC-2 characterizes the variability of a mandibular angle (M-79) and a height of branches (M-70). PC-3 strongly correlates with a height of a symphysis (M-69) and an angle of a chin protrusion (<C’). We found that the Eskimo series have the largest jaws, while the bones from the ancient Egypt and the Tamils series are the smallest. By this we show that PC-1 reveals the presence of ecological gradient on the mandible dimension. We discovered that a mandibular angle and a height of branches are related negatively, therefore jaws with a vertically oriented high branch occupy the maximum values pole and jaws with short inclined branch are in the minimum values region. The first group of jaws pertain to Anglo-Saxons, the other one is typical to Eskimo from Ekven. Hylams’ jaws show the maximum variability along the PC-1 and PC-2. From the PC-3 we obtain the greater the angle of a chin, the higher the symphysis is, and vice versa. Jaws of Eskimo and Hokiens have the highest chin, the jaws of Tamils, Anglo-Saxons and Hylams are low and protrusive.